MySQL匹配具有ASCII版本的Unicode字符 [英] MySQL matching unicode characters with ascii version

问题描述

我正在运行MySQL 5.1.50，并具有一个如下所示的表:

I'm running MySQL 5.1.50 and have a table that looks like this:

organizations | CREATE TABLE `organizations` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` text CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL,
  `url` text CHARACTER SET utf8 COLLATE utf8_unicode_ci DEFAULT NULL,
  `phone` varchar(20) CHARACTER SET utf8 COLLATE utf8_unicode_ci DEFAULT NULL,
  `timestamp` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  PRIMARY KEY (`id`),
  KEY `id` (`id`)
) ENGINE=MyISAM AUTO_INCREMENT=25837 DEFAULT CHARSET=utf8 |

我遇到的问题是MySQL正在将Unicode字符与ascii版本匹配.例如，当我搜索包含'é'的单词时，它将匹配具有'e'的单词，反之亦然:

The problem I'm having is that MySQL is matching unicode characters with ascii versions. For example when I search for a word with that contains an 'é', it will match the same word that has an 'e' instead, and vice versa:

mysql> SET NAMES utf8;
Query OK, 0 rows affected (0.00 sec)

mysql> SELECT id, name FROM `organizations` WHERE `name` = 'Universite de Montreal';
    +-------+-------------------------+
| id    | name                    |
+-------+-------------------------+
| 16973 | Université de Montreal  |
+-------+-------------------------+
1 row in set (0.01 sec)

我从PHP和命令行控制台都得到了这些结果.如何从SELECT查询中获得准确的匹配?

I get these results both from PHP and the command line console. How can I get accurate matches from my SELECT queries?

谢谢！

推荐答案

您将name列指定为text CHARACTER SET utf8 COLLATE utf8_unicode_ci，这告诉MySQL考虑使用 e 和é等同于匹配和排序.排序规则和utf8_general_ci都使很多事情等效.

You specified the name column as text CHARACTER SET utf8 COLLATE utf8_unicode_ci which tells MySQL to consider e and é as equivalent in matching and sorting. That collation and utf8_general_ci both make a lot of things equivalent.

http://www.collat​​ion-charts.org/是很好的资源如何阅读图表，这非常简单.

http://www.collation-charts.org/ is a great resource once you learn how to read the charts, which is pretty easy.

如果要将 e 和é等视为不同，则必须选择其他排序规则.要找出服务器上的归类(假设您仅限于UTF-8编码):

If you want e and é etc. to be considered different then you must choose a different collation. To find out what collations are on your server (assuming you're limited to UTF-8 encoding):

mysql> show collation like 'utf8%';

然后选择使用归类图作为参考.

And choose using the collation charts as a reference.

另一个特殊的排序规则是utf8_bin，其中没有对等项，它是二进制匹配项.

One more special collation is utf8_bin in which there are no equivalencies, it's a binary match.

我知道，唯一不特定于语言的MySQL Unicode归类是utf8_unicode_ci，utf8_general_ci和utf8_bin.他们很奇怪.排序规则的真正目的是使计算机像人们期望的那样进行匹配和排序.匈牙利语和土耳其语字典的条目根据不同的规则排序.指定排序规则后，您可以根据此类本地规则进行排序和匹配.

The only MySQL Unicode collations I'm aware of that are not language specific are utf8_unicode_ci, utf8_general_ci and utf8_bin. They are rather weird. The real purpose of a collation is to make the computer match and sort as a person from somewhere would expect. Hungarian and Turkish dictionaries have their entries ordered according to different rules. Specifying a collation allows you to sort and match according to such local rules.

例如，丹麦人似乎认为e和é等效，但冰岛人却不这样做:

For example, it seems Danes consider e and é equivalent but Icelanders don't:

mysql> select _utf8'e' collate utf8_danish_ci
    -> = _utf8'é' collate utf8_danish_ci as equal;
+-------+
| equal |
+-------+
|     1 |
+-------+

mysql> select _utf8'e' collate utf8_icelandic_ci
    -> = _utf8'é' collate utf8_icelandic_ci as equal;
+-------+
| equal |
+-------+
|     0 |
+-------+

另一个方便的技巧是用一串您感兴趣的字符(在脚本中更容易)填充一列表，然后MySQL可以告诉您等效项:

Another handy trick is to fill a one column table with a bunch of characters you're interested in (it's easier from a script) and then MySQL can tell you the equivalencies:

mysql> create table t (c char(1) character set utf8);
mysql> insert into t values ('a'), ('ä'), ('á');
mysql> select group_concat(c) from t group by c collate utf8_icelandic_ci;
+-----------------+
| group_concat(c) |
+-----------------+
| a               |
| á               |
| ä               |
+-----------------+

mysql> select group_concat(c) from t group by c collate utf8_danish_ci;
+-----------------+
| group_concat(c) |
+-----------------+
| a,á             |
| ä               |
+-----------------+

mysql> select group_concat(c) from t group by c collate utf8_general_ci;
+-----------------+
| group_concat(c) |
+-----------------+
| a,ä,á           |
+-----------------+

这篇关于MySQL匹配具有ASCII版本的Unicode字符的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！